In recent years, there has been a well-known technology, in which, resin optical systems (which are lenses or lens groups), holders (which are body sections), and covers (which are cover sections) of said optical systems are molded by common molding dies. After that these molded members are assembled (Patent Document 1).
According to a technology detailed in Patent Document 1, an optical system (being lenses 35 and 37), a holder (being cylindrical frame 33), and a cover (being cover section 38) are simultaneously molded. While the optical system and the cover are made to remain in stationary molding die (3), movable molding die (4) is moved so that the optical system is inserted into the molded holder, whereby the cover is adhered to them (paragraphs 0026 to 0032).